Fuel injection systems for internalcombustion engines



Aug- 28, 1 w. H. PURDIE El'AL 2,760,334

FUEL INJECTION SYSTEMS FOR INTERNAL-COMBUSTION ENGINES Filed March 5. 1,952 6 Sheets-Sheet 1 [IN ell fan: 1 am A amilhn Hirdl'e FPI-cy Jackson V X /Y 4 14,

Aug. 28, .1956 w. H. PURDIE ET AL 2,760,334

FUEL INJECTION SYSTEMS FQR INTERNALCOMBUSTION ENGINES Filed March 5, 1952 6 Sheets-Sheet 2 Inrewfars 1956 w. H. PURDIE ETAL 2,760,334

FUEL INJECTION SYSTEMS FOR INTERNAL-COMBUSTION ENGINES Filed March 3, 1952 6 Sheets-Sheet 3 l/zrewfons' Aug. 28, 1956 w. H. PURDIE ETAL 2,760,334

FUEL INJECTION SYSTEMS FOR INTERNAL-COMBUSTION ENGINES Filed March a. 195' e Sheets-Sheet 4 lm/emlorw Willi an; lfoai ardle 9* Percy 4/?(1'000 @fldq 4A1 Aug. 28, 1956 w. H. PURDIE ETAL FUEL INJECTION SYSTEMS FOR INTERNAL-COMBUSTION ENGINES 6 Sheets-Sheet 5 Filed March 3, 1952 g- 1956 w. H. PURDIE ET AL 2,750,334

FUEL INJECTION SYSTEMS FOR INTERNAL-COMBUSTION ENGINES Filed March 3, 1952 6 Sheets-Sheet 6 &

\F i In W fam- WzYI/am Hamilton Pardze 5 Perry Jackson 2,760,334 Patented Aug. 28, 1956 Fice FUEL INJECTION SYSTEMS FOR INTERNAL- COMBUSTION ENGINES William Hamilton Purdie and Percy Jackson, Sunder-land,

England, assignors to William Doxford and Sons Limited, Sunderland, England, a British company Application March 3, 1952, Serial N 0. 274,602

Claims priority, application Great Britain March 5, 1951 6 Claims. (Cl. 60-46) The invention relates to large air-less injection internal combustion engines operating on the diesel or semi-diesel cycles and is concerned with such engines of the two cycle multi-cylinder marine reversing type having an engine-driven cam-shaft for operating starting air valves and usually other devices such as lubricators and also having one or more engine-driven fuel injection pumps for each cylinder.

For various reasons it is convenient, in engines of the above type, to employ the cam-shaft to drive the fuel pumps. Thus, it is desirable that the fuel pumps be positioned adjacent to the engine cylinders to reduce the length of the connecting pipe lines and the cam-shaft is usually suitably located for driving pumps so positioned. Further, if the cam-shaft is used to drive the pumps the need to provide an additional drive from the engine crank-shaft is avoided.

Fuel pumps such as are usually employed in engines of the above type (i. e. jerk pumps) deliver fuel at full load through a maximum of about 20-24 of crank angle and the rate of doing Work is so high that a heavy driving shaft and a heavy drive thereto are required. Such a shaft and drive are not practically satisfactory for operating the cams and it is now customary to locate the fuel pumps low-down adjacent to the crankshaft with a separate short, sturdy drive thereto.

The present invention provides a two-stroke cycle, multi-cylinder, marine, reversing diesel engine having an engine-driven cam-shaft for operating starting air valves and also having one or more engine-driven reciprocatory fuel injection pumps for each cylinder characterised by the features that the fuel pumps are of the accumulator type and are operated by cams, eccentrics or other means from the engine cam-shaft.

The expression accumulator pump" is used herein to mean a pump or pump installation in which the pump output or a part of it is stored under pressure during the pump stroke and the storage pressure is employed to inject the stored fuel into the engine cylinder. The working stroke of such a pump may extend over, say, 120 of crank angle, so that the rate of work required is very much less than is needed for a jerk pump and the requirement for an excessively sturdy cam-shaft to drive it is avoided.

The pump valves may also be operated from the cam shaft.

In one form of the invention each pump has inlet and discharge valves constituted by ports in the cylinder wall covered and uncovered at appropriate times in the pump cycle by the pump piston.

A further disadvantage of engines of the above type as at present constructed is that heavy reversing mechanism is required for the jerk pumps. This disadvantage is avoided in a preferred form of the invention in which a symmetrical arrangement of driving means for the pumps and their valves is employed.

Some specific constructions of engines according to the invention will now be described by Way of example, and with reference to the accompanying drawings in which:

Figures 1A and 1B show a front elevation of a marine engine,

v Figure 2 shows a section through a combined fuel pump and accumulator used in the engine shown in Figure 1,

Figure 3 is a rear view, partly in section, of the pump shown in Figure 2,

Figure 4 shows a section through a second form of fuel pump and accumulator, and

Figure 5 shows a section, in a diiferent plane from that of Figure 4, through a further form of fuel pump and accumulator.

The engine forming the subject of the first example is shown in Figures 1 to 3. The engine is a three-cylinder, opposed piston, reversing marine engine operating on the full diesel cycle, with air-less injection. Each of the cylinders 1, 2, 3 has a combined pump and accumulator shown at 4, 5 and 6. The three pumps are driven from a common camshaft 7 driven by a chain 8 from the engine crankshaft. All the accumulator chambers of the pumps are interconnected by a pipe (not shown) and they are all connected to a single charging pump 10 also driven from the shaft 7 and arranged to maintain pressure in the accumulator chambers of the pumps. If desired a second charging pump may be provided and the two pumps may be used simultaneously or alternatively.

The cam-shaft 7 also operates, in well-known manner, valves for submitting starting air to the cylinders and mechanical lubricators for the engine parts.

All three accumulator pumps are alike in construction and operation and only one will be described in detail. The pump is shown in Figures 2 and 3 and has a plunger 12 operated by an eccentric 13 on the camshaft 7 of the engine and the measured quantity of fuel to be injected is trapped in the space 14 during upward movement of the plunger and when the suction valve 15 has been permitted to seat by the cam 16 and thus to prevent escape of fuel from the space. Above the space 14 there is a free plunger 17 of which the lower end is subjected to the pressure of the fuel in the space 14 and the upper end is subjected to the pressure of oil in an accumulator chamber 19. This chamber is, as stated already, connected to the charging pump 10, the inlet to the chamber being at 29.

The charging pump 16 is driven by a cam on the shaft 7. The pump delivers oil into the chamber 19 to maintain the pressure in the chamber. The pressure may be varied by varying the output of the pump.

The lift of the free plunger 17 will vary according to the amount of fuel injected (i. e. according to the load on the engine) and a tell-tale plunger 32 is provided, in this example, at the upper end of the plunger 17 to indicate the travel of the plunger 17 and thereby to show that this is correct according to the load and to indicate that all the plungers are rising by equal amounts.

A spring 33 is provided in the accumulator chamber 19 engaging with the plunger 17 to augment the action of the pressure in the chamber and to ensure that there is a minimum injection pressure should there be a failure in the delivery of the pump 10.

In the operation of the engine the plunger 12 traps in the space 14 a quantity of fuel determined by the position in the stroke of the plunger at which valve 15 is allowed to seat. The pressure of the fuel in the space 14 is equal to that of the oil in the chamber 19 plus the pressure due to the spring 33. When the delivery valve 34 of the pump is opened by cam 35 on shaft 7, the plunger 17 falls rapidly under the action of the pressure in the chamber 19 and the spring and the fuel in the space 14 is injected into the engine cylinder.

armrest The position in the upward stroke of the plunger 12 at which the snctioii'v'alve 'l'5 "is "a110wed'rd'seatana; consequently, the amount of fuel delivered by each stroke is. variable by rotation of an eccentric 3Q. n; a shaftjfil rotatable from. the'engin. 'contrqlfgear '26, by. l 'r l wq s 3 h t mi g (if h pcn g b t l shar' valve 34 is simultaneously variable, in' like manner... means of an eccentric 3.3. on the shaft 31.

""Thei puinnplung'er. moves upjwamiy' on its pumping stroke o'v'er"l80 ofthe cam-shaft rotation. "Thefportion pf, the stroke. which is actually empleyedpumping ('i. e'. the portion during which subStaHtial driving torque is required) varies according t0. the; panama the stroke at which valve 15 is allowed te seat Thiejgortion at full load normally however takes aliio l t T20, of the ft rot tiqnfwhich is much greater. than that tak by a jerk-type pump. Consequently the mald mltm. t qu req re s m ch r fia an?! a c m v{ t of me 'cally'sjatistac'tory dimensions may be nsed. Fi j'ref4 shows another tZOQStmCIlQn of 'fuel'which may 'be'use'd in 'place'of that r in Figures 2' and 3. and. whid n V w Of i s m it i to pre e rerf sy applications. The pump is, as in the previous i p f v n om he. shaft 7 y' an ccen r c 0. l fmat f numnpl n er' 4.1- This p u ge is'al'so rotatable means of a rack 42 engag'ng with pinion teeth"43 on the plunger, the rack being reciproarena. by u tab e n means, r m th ine nt l ge 2 6 'Theplunger'fl is formed; at itsi'upper end, wi h a r es 1 .2 b n e 1 16; by a hel a st p 143'. step co -fop'erat es with a port 44-; in the cylin; der wall leading back'to the fuel supply, to close the port at a position in' the stroke of the plunger 41 depending upon the rotational ppsitionv of the plunger. Hence the amount of fuel trapped in the space 46 an'dpl lmped, may Beve a e. The plunger also has a central passageway 45 leading'to a circumferential groove 47 which registers with a discharge port atthe' upper limit of'move'ment of 't ep j r- Opposed to; the plunger 41 there is a free plunger. Q which 'is'urged downwardly; as in' the previous example; by hydraulicpressure in achamber Stand by a spring "In; the operation of the pump, fuel is drawn into the cylinder during the downward stroke of plunger 41 and, during the first part of the upward movement a portion of thisfuel (the, amount depending iipon the rotational position of the plunger) is returned" to: the supply through 'port'44. The remainder or the fuel is trapped in space 46 and further movement ofthe plunger 4l auses plunger 56 to be raised. 'When groove 4. 7 registers with port 48' the. plunger 50; rapidly descends and"f6rces the' trapped fuel through thefdischarg'e port i s to the injection nozzle.

Figured shows a modification of the pump shown in Figure-"4. The arrangement of the pump" plunger 41, the driving means and the co-operating ports'in the cyl inder-Wall is"substantially' as described withrefer ence to Figure '4, andsimilar, reference numerals have been applied to" the correspondingparts in both figures.

In this modification the upper end of'the upper. plunger 50 is provided with an enlarged head 60. whichoperates, "njin a' chamber 61. A-irorother gas isr'naintained in the chamber 61 above the piston under. pres safer-say 600 lbs! per' square inch). The ratio be tween the area of thepiston -6trand'the area ofthe plunger 50: determines theinjec'tion pressure of the" fuel onfthe underside of the plunger 50. The pressure in the chamber may be'obtained" from any convenient source such, as; the starting air storage bottles of the engine, or from an auxiliary air compressor'driven by the engine or other means-or the gas may be bled-off. from theengine cylin deririeach-casethe gas being fed to the chamber through, the opening 62 The pressure'in the accurmllatedcham; b'r may "be regulated by a reducing. valve. or; a; stop,

valve. The piston 60 may be sealed by leather cup washers 6 i as sliown orbypiston rings. With his example the pump ltl may be omitted.

In each of the above examples the eccentric which operates the pump and the eccentric or cams, when provided, which operate the valves, are all symmetrical. That is. to say, thG-pumps will operate with the same timing with respect to the engi icpistons for" each direction of rotation,conseiiuentlythe need for reversing mechanisrrr to operate the pnmpl is avoided. The ingof the pumps is suchtha-t the injectionof the fl el begins atfor immediately before, the endofthe engine es i t k a 2 111 Pis n rea hes th d of its upward stroke to coincide with the end' of the engine compressionstroke; The end of injection is determined by the exhaustion of the; accumulated fuel and is independent of the closing of the pilmp discharge valve which occurs later.

We aim:

1 In. a: two-stroke. cycle multi-cylinder. marine re. versing; diesel engine of;v the; type having an engine-driven cam shaft arranged adjacent the. cylinders of the; engine and; provided with cams for operating air-startingval'ves, the, improvement comprising at least one. accumulator type. pump. for. each cylinder adapted to supply. fuel thereta and cam means on the cam shaft operating'said accumulaton pumpsin synchronisrn with the engine,

2.. In; a two strokecycle mnlthcylinder, marine rer versing engine of the: type having. a crankshaft; upright cylinders. arrangedi in line along the crankshafit; an eng ne-driven cam shaftarr-anged adjacent the cylin-, ders and; parallel to.- the, engine. crankshaftv and proyided' w th ar- Qncr g: ir-st r g valve i -v provement. comprising at least one injection. pump. of the accumulator type for each cylinder adapted. to. supply. fuel. thereto andv cam means on the cam shaft B. flsr a fi sq u a r P mp in sy ch o i m wi h en e.v

1.111 a WQiS I-QK cy w t y n er ma ine rcversing diesel engine of the. type having;v an engine-driven shat arrangegt; adjacent the cylinders, of. the engine prov ded with earn s for operating. air-starting valves; a mv rnt c m is n a t: one w u awr type pump for each cylinder adapted; to supply fuel there to under. pressure. and; cammeans. on; the cam; shaft la iet na a a cu ula r r mp n sy chro sm w the 'engjpe, said; cams being termed. so, as to. cause the {ramps to aworking load over approximately car ia die l; n ne f t yp having a engine driven cam shaft arranged adjacent. the cylinders; of; the naiae a d; prov d d; w th c ms er. operating air-starting valves, the improvement comprising at 'leastone fuel; in: a; .011} Pum f: h c u u to yp or each y ind ad n e o su n riu lf r o. inlet and di harg v lves on,- said, pump. andcam means operating said? pump: and inlet; and discharge valves insynchronism; with. the; engine;

5. In a two strokecycle; multi-cylinder marine revere; ns; ifisel; n ne 01- h pe h v n an, enemariven can! shaft; arrangedv adjacent the cylinders of the. engine and provided with cams for operating air-starting; valves, e man nt m si g.- at a t ne jec of the accumulator type having a pump piston; in

was inde w th. le nd; s-r ea ra e in the ulge y en. e. new: b n wve n Be ame 4 ,11 he-am Waleh P1 1 P Qn a vns mn m th the engine cylinders and'c am's on the camshaft operating said pump pistonin synchronism theenginecylinders. 6.. In oke. cycle. m iltiecylinder. marine. levers; v e'of. the. type. haying an. ngine driycn Haiti arr nged. adjacent. thecylinders. of i the. engine a; M ram mangerta es; the improvement comprising at least one, reci rt;

ns-sa a aver a r ag. r ne 5 ing inlet and outlet ports, a free plunger in one end of said chamber, resilient means urging said free plunger into said chamber and a pump plunger in the other end of said chamber, said ports being arranged so that the inlet port is covered by the pump plunger in the latter part of its inward pumping stroke whereby fuel trapped between the two plungers is accumulated during the remainder of the pumping stroke under pressure from the free plunger and the outlet port being uncovered by the pump plunger at the end of the pumping stroke whereby the accumulated fuel is then forced out of the chamber under pressure through the outlet port, and cam means on said shaft for operating said pump plunger.

References Cited in the file of this patent UNITED STATES PATENTS Carter Mar. 25, 1919 Petersen Dec. 15, 1931 Elwell Feb. 14, 1933 Simmen July 25, 1933 Sprado Feb. 5, 1935 Retel Dec. 17, 1940 FOREIGN PATENTS Switzerland Jan. 2, 1933 Great Britain Oct. 5, 1933 France Jan. 29, 1934 

